LED resistance question

[CarlW]

It looks involved!

Dave Rob might have a better opinion on what is going there.

Picture 3 of 6 - looks like two wires coming from a transformer to the light PCB plug?
Blue connected to white and black connected to yellow.
Can't read the transformer, but is the transformer connected to anything else?
Does transformar have any meaningful text on it?

Picture 6 of 6, there are 20 relays on a board and 2 more to the left of picture. Any meaningful text on the relays?
Any idea which 16 relays are connected to the light bulbs? Am I correct that each relay has 14 wires going to it?

My guess is the power goes to the switch, if the switch is closed, the light turns on AND the relay coil is energized.
What the relay does? I don't know.

One other idea, the bulbs you had the burning smell with, how many amps were they rated for? You can buy 30V bulbs (would work fine with 28V); they come in at least two currents standard - .1A or .05A. Maybe you could just change to .05A 30V bulbs? They are also slightly longer than regular bulbs. I have used them in 24V power flashes and they fit ok and worked ok.

Have you checked to see if the LED bulbs fit in the game, they are wider and longer than typical incandescent bulbs.

You want answers and all I have is more questions...

[daverob]

Dave Rob might have a better opinion on what is going there.

Thanks for the vote of confidence, but I'm no expert on this era of machines so I'd only be making guesses and your description makes enough sense to me.

BTW my guess would be that the switches activate the lamp and relay, and the relays are used to 'latch' the switch contacts. ie the switch is closed which activates and closes the contacts on the relays, one of the relay contacts is also wired across the switch, thus effectively holding the switch closed even after the ball has passed through. There will be another set of relay contacts (or a push to break switch) which will remove the power to these relays, thus resetting the 'latches' and turning the lamps off.


Another thing that I thought of was that you can't put a single resistor in the 'ground' connection as the voltage drop would vary depending on how many LEDs are lit, but you could do it with a zener diode, as the voltage drop across the diode would always remain constant even with the changes in current due to the number of lit LEDs. You'd have to figure out the power ratings of the LEDs and how much power the zener diode would have to dissipate if all the LEDs were on at the same time, but it could be feasible and would be easier to wire in than rewiring all of the wires going to the edge connector via a resistor.

It's not the conventional way of using a zener diode to set the voltage in a circuit. But I use zener diodes in a similar way in my dongles as the voltage supplied to the dongle by the pachinko machine is too high to feed directly to the voltage regulation circuitry.


On the other hand if I was going the individual resistor route, then I'd probably use a scalpel or craft knife to cut the tracks on the lamp PCB near the edge connector and solder a surface mount resistor across the cut in the track. While surface mount components are a little bit fiddly to work with, it's got to be easier than soldering a resistor into a wiring harness.

[pachiwall]

Thanks for the vote of confidence, but I'm no expert on this era of machines so I'd only be making guesses and your description makes enough sense to me.

BTW my guess would be that the switches activate the lamp and relay, and the relays are used to 'latch' the switch contacts. ie the switch is closed which activates and closes the contacts on the relays, one of the relay contacts is also wired across the switch, thus effectively holding the switch closed even after the ball has passed through. There will be another set of relay contacts (or a push to break switch) which will remove the power to these relays, thus resetting the 'latches' and turning the lamps off.


Another thing that I thought of was that you can't put a single resistor in the 'ground' connection as the voltage drop would vary depending on how many LEDs are lit, but you could do it with a zener diode, as the voltage drop across the diode would always remain constant even with the changes in current due to the number of lit LEDs. You'd have to figure out the power ratings of the LEDs and how much power the zener diode would have to dissipate if all the LEDs were on at the same time, but it could be feasible and would be easier to wire in than rewiring all of the wires going to the edge connector via a resistor.

It's not the conventional way of using a zener diode to set the voltage in a circuit. But I use zener diodes in a similar way in my dongles as the voltage supplied to the dongle by the pachinko machine is too high to feed directly to the voltage regulation circuitry.


On the other hand if I was going the individual resistor route, then I'd probably use a scalpel or craft knife to cut the tracks on the lamp PCB near the edge connector and solder a surface mount resistor across the cut in the track. While surface mount components are a little bit fiddly to work with, it's got to be easier than soldering a resistor into a wiring harness.

the balls that land in the pockets do not "pass through". A trap door retains the balls in the pocket. The 1st ball in the pocket holds the switch closed until a coin is inserted and the START SOLENOID opens the trap door, releasing the balls into the track behind the window.
I never thought of a zener diode...because I am more mechanical inclined than electrical inclined. What value (is that the correct term) diode would be required...based on the information I will provide in my next post when I perform the tests you taught me to do.
I had considered cutting a trace, drilling 2 holes per circuit, and mounting a traditional resistor thru the board, soldering it to the traces. I rejected that idea because, splicing into the wiring harness is easier to reverse if I make a mistake. Once I start hacking the bulb board...it becomes HARD to reverse. As far as the surface mount resistors...I did not expect them to have enough wattage (correct term?) to handle such a voltage drop. i could be wrong.

[pachiwall]

Thanks for the vote of confidence, but I'm no expert on this era of machines so I'd only be making guesses and your description makes enough sense to me.

BTW my guess would be that the switches activate the lamp and relay, and the relays are used to 'latch' the switch contacts. ie the switch is closed which activates and closes the contacts on the relays, one of the relay contacts is also wired across the switch, thus effectively holding the switch closed even after the ball has passed through. There will be another set of relay contacts (or a push to break switch) which will remove the power to these relays, thus resetting the 'latches' and turning the lamps off.


Another thing that I thought of was that you can't put a single resistor in the 'ground' connection as the voltage drop would vary depending on how many LEDs are lit, but you could do it with a zener diode, as the voltage drop across the diode would always remain constant even with the changes in current due to the number of lit LEDs. You'd have to figure out the power ratings of the LEDs and how much power the zener diode would have to dissipate if all the LEDs were on at the same time, but it could be feasible and would be easier to wire in than rewiring all of the wires going to the edge connector via a resistor.

It's not the conventional way of using a zener diode to set the voltage in a circuit. But I use zener diodes in a similar way in my dongles as the voltage supplied to the dongle by the pachinko machine is too high to feed directly to the voltage regulation circuitry.


On the other hand if I was going the individual resistor route, then I'd probably use a scalpel or craft knife to cut the tracks on the lamp PCB near the edge connector and solder a surface mount resistor across the cut in the track. While surface mount components are a little bit fiddly to work with, it's got to be easier than soldering a resistor into a wiring harness.

the balls that land in the pockets do not "pass through". A trap door retains the balls in the pocket. The 1st ball in the pocket holds the switch closed until a coin is inserted and the START SOLENOID opens the trap door, releasing the balls into the track behind the window.
I never thought of a zener diode...because I am more mechanical inclined than electrical inclined. What value (is that the correct term) diode would be required...based on the information I will provide in my next post when I perform the tests you taught me to do.
I had considered cutting a trace, drilling 2 holes per circuit, and mounting a traditional resistor thru the board, soldering it to the traces. I rejected that idea because, splicing into the wiring harness is easier to reverse if I make a mistake. Once I start hacking the bulb board...it becomes HARD to reverse. As far as the surface mount resistors...I did not expect them to have enough wattage (correct term?) to handle such a voltage drop. i could be wrong.

[pachiwall]

It looks involved!

Dave Rob might have a better opinion on what is going there.

Picture 3 of 6 - looks like two wires coming from a transformer to the light PCB plug?
Blue connected to white and black connected to yellow.
Can't read the transformer, but is the transformer connected to anything else?
Does transformar have any meaningful text on it?

Picture 6 of 6, there are 20 relays on a board and 2 more to the left of picture. Any meaningful text on the relays?
Any idea which 16 relays are connected to the light bulbs? Am I correct that each relay has 14 wires going to it?

My guess is the power goes to the switch, if the switch is closed, the light turns on AND the relay coil is energized.
What the relay does? I don't know.

One other idea, the bulbs you had the burning smell with, how many amps were they rated for? You can buy 30V bulbs (would work fine with 28V); they come in at least two currents standard - .1A or .05A. Maybe you could just change to .05A 30V bulbs? They are also slightly longer than regular bulbs. I have used them in 24V power flashes and they fit ok and worked ok.

Have you checked to see if the LED bulbs fit in the game, they are wider and longer than typical incandescent bulbs.

You want answers and all I have is more questions...

The item that looks like a transformer is a solenoid that opens a trapdoor that holds the balls in the lower numbered pockets. I refer to this part as the START SOLENOID. Whenever a coin is inserted, it pulls up on a wire that opens the trapdoor. The relays on the relay board are labeled "OMRON type MY4". There are 14 blades and one stud, I am not sure if the stud is a conductor or not.DSCF8717.JPGDSCF8720.JPGDSCF8721.JPGDSCF8723.JPG I have not tried to find out which relays are for the grid lights. Not to mention, what are the other 4 relays for? There are the scoreboard lights...but that is 9 bulbs. Plus there is a "low ball" bulb and a "wait" light...only 2.
My guess is similar to yours. I believe power goes to the switch, if the switch is closed, the light turns on and the relay coil is energized. When another coin is inserted, or the payout button is pressed, the "WAIT" light comes on and you can hear the motor on the relay board turning. It has a contact arm that rotates and touches a conductor for each relay...if the relay coil is energized, the machine kicks out a coin. Because of this analog action...you can hear the motor "clicking"then kick out a coin, click some more, kick out 2 coins, click some more, etc. Since this is an early design, and has no computer the relays are how the machine keeps track of things. I am sure there was a more technical way to explain that...but I don't know what it is.
I have considered higher voltage incandescent bulbs but I haven't looked for any. The original bulbs are 28 volts 2 watts. The replacement bulbs are labeled "C1821 CHINA".
Yes, I have test fitted the bulbs to frame. They are larger...but they do fit.